Self-cooling fluid containers are known to include, generally, a first chamber which contains a beverage to be cooled, a second refrigerant-containing chamber in thermal contact with the first chamber, a refrigerant dispersal assembly, including a third chamber which provides a volume for the refrigerant to expand into upon its release from the second chamber, and cooling activation means for establishing a fluid path between the refrigerant region to the dispersal region. Upon release of the refrigerant from the second chamber, the fluid in the first chamber is adiabatically cooled as a result of thermal contact between the refrigerant in the dispersal region and the fluid in the beverage chamber.
U.S. Pat. No. 5,214,933 to Aitchison et al. and U.S. Pat. No. 5,555,741 to Oakley, each assigned to the assignee of the present invention and hereby incorporated by reference into this application, disclose self-cooling fluid containers.
The Aitchison et al. patent discloses a capsule-type refrigerant chamber which extends into the fluid region of the beverage container. This design provides substantial heat transfer surface area between the fluid to be cooled and the refrigerant capsule. However, the possibility of leakage of the refrigerant into the fluid container, although highly unlikely, must be prevented.
The Oakley patent discloses a refrigerant chamber which is integral with the base of the beverage-containing chamber. Such an integrated design eliminates the need to separately manufacture, store and assemble multiple components. However, the walls of the integral capsule must be sufficiently thick to contain the pressurized refrigerant safely, thus increasing the cost of the container. Also, the integrated design requires that the refrigerant, which is relatively expensive, be introduced into the container during the manufacturing process prior to pasteurization and final quality control checks. If a container is found to be defective, it must be discarded from the production line, and the refrigerant charged thereinto must be either discarded or retrieved, at considerable expense.
French Patent No. 513,015 to Sterne discloses a beverage bottle or other fluid container which includes a hermetically sealed chamber containing chemicals which mix and react to effect heating or cooling of a fluid in contact with the chamber. The hermetically sealed chamber appears to be a generally cylindrical independent structure within a recess of a similar shape in the fluid container. The contents of the hermetically sealed chamber remain inside the chamber, even after they have combined to initiate the chemical reaction. Leakage of the chemicals into the fluid chamber is thus a potential hazard. In addition, the chamber is not removable from the fluid container and must therefore be manufactured with the container. Moreover, the sealed chamber cannot be reused after the chemical reaction has occurred. Disposal of the chamber may be problematic, depending on the integrity of the chamber and the nature of the chemicals therein. In addition, the chamber is not designed to withstand the storage pressures characteristic of liquid refrigerants and other pressurized substances.
Accordingly, it would be an advancement in the art of self-cooling fluid containers to provide a self-cooling fluid container having a refrigerant chamber that is entirely separate and removable from the beverage-containing chamber.